Photochemical removal of uranium from a phosphate waste solution

Abstract

A photochemical method to remove uranium from a phosphate containing waste in high yield is reported. The solution resulting from the titrimetric assay of uranium consists of approximately 1 g dm⁻³ uranium in phosphoric acid (3 mol dm⁻³). UV illuminated titanium dioxide in a deaerated and 25 fold diluted waste solution (40 ppm uranium) containing a hole scavenger (methanol) almost completely (98%) removed uranium from solution at pH 2 in six hours. The product was found to be free of phosphate and resulted in a grey colouration of the titania. Re-dissolution of the uranium occurred in an aerated environment over the course of a week. These results demonstrate the basis for an environmentally friendly method to photochemically reduce and remove uranium from solutions containing strongly co-ordinating ligands.